Identification Guide

Marine mammals can be difficult to identify at sea. Even under ideal conditions, an observer often gets little more than a brief view of a splash, blow, dorsal fin, head, flipper, or back, and this is often at a great distance. Rough weather, glare, fog, or other bad sighting conditions compound the problem. Many species appear similar to another, especially in the brief glimpses typical at sea. Animals of some poorly known groups (most notably beaked whales and Southern Hemisphere fur seals) are especially difficult to identify to species, even with a good look at a live animal or an “in hand” specimen. For all these reasons, even experts often must log a sighting as “unidentified” or on an easily confused pair or group of species. In all cases, this designation, accompanied by a detailed description is preferable to recording an incorrect identification.

The species identification sheets in this guide are designed to be the primary tool used in identifying marine mammals observed at sea. A dichotomous key to marine mammals observed at sea would be virtually worthless, because of the lack of useful cues for most sightings and the variability of marine mammal behaviour. Marine mammal identification at sea is something that must be learned through doing. Experienced marine mammal observers, like birders, often will be able to make an identification based on a composite of characteristic features including behaviour, and personal knowledge of the local marine mammal fauna. This ability will come with experience, guided by working with seasoned observers and the use of a proper field guide.

Character Matrix 1:Beaked DolphinsWITH prominent markings. All these species are about2m long.